Technical Field
Embodiments of the subject matter disclosed herein relate to a cooling arrangement for a motor of a vehicle.
Discussion of Art
Heavy-duty vehicles for harsh and/or hazardous environments may include electric motors (e.g., electric traction motors) that require cooling. Such vehicles may include underground mining vehicles such as load-haul-dump vehicles, haul trucks, and ancillary vehicles such as coal scoops, drilling jumbos, or the like. In one example, these vehicles may be battery electric vehicles that are driven only by the electric traction motor and not by additional engines (e.g., diesel engines). In such vehicles, the electric motors may be required to be sealed. Thus, cooling of these electric motors is generally limited to passive approaches, such as natural convective non-ventilated cooling, and active approaches including fan-cooling, forced air over the motor frame via a blower, and various others incorporating an intermediate cooling medium and heat exchangers, such as liquid-cooling and air-to-air heat exchangers. However, with the exception of convective non-ventilated cooling, these cooling approaches may introduce maintenance requirements and/or failure modes, especially in underground mining environments (e.g., rock dust, moisture, or the like). While totally enclosed convective non-ventilated cooling (TENV) motors are beneficial for underground mining because they are sealed from the environment and have no moving parts, filters, or secondary cooling, they also tend to be larger and heavier than actively-cooled motors of the same torque and power ratings (due to requiring increased surface area for cooling and reduced loss densities). The large weight and size of TENV motors present design challenges on the vehicle, often resulting in a less capable vehicle or requiring additional cooling systems. In one example, adding cooling fins to an exterior of the motor frame may increase motor cooling. However, these fins increase the overall effective size of the motor, as well as increase the trapping of debris such as rock dust on the fins, thereby decreasing their cooling effectiveness.